Response to issue #32810
Use of the .bg-white class to define visual aspects of the examples
would be unintuitive for theme builders to test themes on.
This replaces instances of .bg-white with .bg-body in the examples.
- Edited examples to replace use .bg-white class with .bg-body class
- product
- offcanvas
- pricing
- cheatsheet
- cheatsheet-rtl
- Edited utilities colors.md & shadows.md to include .bg-body class
Replaces shorter examples with more sensible/representative/inforrmative text. For longer passages, resorted to using SFW extracts from http://katyperryipsum.com/
